23-03-2011, 12:42 PM
PRESENTED By
SUDHAKAR AKKI
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SPACE VECTOR MODULATION FOR TWO LEG INVERTERS
INTRODUCTION
• Semiconductor switches mainly determine the overall price of power converters.
• The main objective of this project is to prove 2leg inverters are the best option for low power applications for getting the good performance.
• Two leg inverter produces the square wave or quasi-square wave. but low power applications allow the two leg inverter output.
• In many industrial applications, it is often required to vary the output voltage of the inverter due to the following reasons
To cope with the dc I/p voltage.
To regulate the voltage of inverters
To satisfy the constant voltage & frequency for control requirement.
Space vector modulation
• In sinusoidal PWM, the inverter can be thought of as three separate push-pull driver stages, which create each phase waveform independently.
• SVM, however treats the inverter as a single unit
• The space vector method is a d,q model PWM approach
Modulation index is high
SVM produces 15% higher then the sinusoidal PWM in output voltages
Simple, inherently digital calculation of the switching times.
SVPWM has been gaining more attention in the industry.
Block diagram of the project
• Switching times of each sector
• Sectors for 2-leg inverter
• Connotative Modulation Functions for 2leg
CONCLUSION
• In this dissertation work, it is shown that two-leg inverters are the best option for high performance low power applications. It can be resolved by comparing the no of semiconductor switches usage in 2-leg and 3-leg inverters and moreover two leg inverters allow the asymmetrical voltages
• To enable this, space vector pulse width modulation (SVPWM) technique for two-leg and three-leg inverters is presented.
